Two Russian military pilots have died after their helicopter crashed near the central Syrian city of Homs.

The aircraft, an M-28H attack helicopter, was not shot at, Russia's defence ministry said.

The crash happened in the early hours of Tuesday, the ministry said. The bodies were recovered and brought to Russia's Hmeimim air base.

Russia joined the Syrian conflict in September, launching air strikes in support of President Bashar al-Assad.

A "cessation of hostilities" came into force in February including the Syrian government and nearly 100 rebel factions, but not the so-called Islamic State (IS).

Russia withdrew most of its forces from Syria but officials said in March they would continue air strikes.

More than 250,000 Syrians have been killed in nearly five years of civil war. Millions more have been displaced.